Fiber optics are used in catheters and probes for the purpose of transmitting light into and receiving light from internal regions of the body. Because a catheter or probe must be sized to be received within a vein or artery, the fiber optics used within such an apparatus must also be of very small diameter.
For example, a catheter or probe may include an elongated tube having proximal and distal openings and fiber optic means in the form of one or more fiber optic light conductors in the passage and extending through the proximal opening to provide a proximal section of the fiber optic means outside of the tube. The fiber optic means is coupled to a connector body, and the connector body is received within a cavity of a receptacle which optically couples the catheter to an instrument. The receptacle may be considered as part of the instrument. The instrument may, for example, provide a source of light for transmission through the catheter and the necessary equipment to process a light signal received from the catheter.
One problem with this construction is the mounting of the fine fiber optic light conductors on the connector body. The fiber optic light conductors each of which comprises one or more optical fibers, must be located with respect to the connector body with great precision and securely retained in position. This is necessary so that light can be transmitted efficiently between the instrument and the catheter. Locating the fiber optic light conductor on the connector body with precision is difficult because of the small diameter of the optical fibers.
It is also important to assure that the connector body is tightly seated within the receptacle. If this is not done, losses will occur at the interface. Moreover, the connector body and receptacle must cooperate with each other to precisely position the connector body within the receptacle to maximize the optical coupling between the optical fibers in the connector body and in the receptacle.
More specifically, it is important that the connection of the connector body to the receptacle be stable so as to preclude, insofar as possible, relative movement between the connector body and the receptacle of the type which would effect the optical signal. It is also important that the coupling of the connector body to the receptacle provide reproduceability, i.e., provide the same relative orientation of these two members each time the connector body is inserted into the receptacle so that the optical signal provided does not vary as a result of reinsertion of the connector body into the receptacle.
In one prior art device, the connector body is held within the receptacle by a spring door. This prior art device does not provide the stability and reproduceability that are desired. In addition, the spring door can be difficult to clean, thereby making reuse of the receptacle somewhat more difficult.